Enteric viruses generally refer to all types of viruses that may have serious medical effects because they primarily infect the gastrointestinal tract through the human mouth when the natural environments like water and soil are contaminated, and then spread to various sites in the body. In recent years, approximately 100 types of enteric viruses have been classified. Among these, the enteric viruses typically include norovirus, rotavirus, hepatitis A virus (HAV), coxsackievirus, astrovirus, adenovirus, etc.
Norovirus is a representative pathogen that causes food poisoning in the winter, and has a positive single-stranded RNA genome. It has been reported that norovirus causes at least 50% of waterborne and foodborne poisoning incidents which occurred between the years 2007 and 2009. Upon infection, its main symptoms include nausea, vomiting, stomachaches, diarrhea, pyrexia, etc. In rare cases, the elderly, patients, and the like may die from the effects of serious dehydration. The infection may be caused via a wide variety of routes of infection, that is, caused through interpersonal contact, feces, the mouth, and potential aerosol infectivity, and caused through contaminated water and foods, and there are a variety of virus variants. Concurrent infections by two or more variant noroviruses often occur when fish and shellfish are contaminated or water is contaminated.
Rotavirus is a virus that has a double-stranded RNA genome consisting of 11 segments, and causes rotavirus enteritis which annually kills more than 600,000 people worldwide. In general, infants under five years old are infected with rotavirus. Upon infection, its main symptoms include dehydration caused by a disorder such as acute diarrhea, and thus patients of developing and underdeveloped countries have a high death rate because the patients are not rehydrated when they have a symptom of dehydration. Rotavirus is a virus which has been regularly reported to the surveillance system run by the Korea Centers for Disease Control and Prevention.
Hepatitis A virus has a single-stranded RNA genome, and as a waterborne virus, is manifested by mild cold symptoms, jaundice or severe gastrointestinal symptoms such as stomachaches, vomiting, and diarrhea upon infection. The hepatitis A virus has become a big problem as its infections have surged in developed countries with good hygienic conditions. In the case of Korea, from 2005 to 2009, incidence has increased 19 fold, rapidly increasing from 789 in 2005, 2,081 in 2006, 2,233 in 2007, 7,895 in 2008, and to 15,041 in 2009. Waterborne viruses are generally found in age groups with weak immune systems, such as infants, the elderly, etc., but unusually, the age group of 20 to 30 accounts for 79% of hepatitis A virus incidence.
Coxsackievirus is a virus that has a single-stranded RNA genome and is usually transmitted through oral infection between young children in summer. Upon infection, its representative symptoms include gastrointestinal symptoms such as pyrexia and vomiting, diarrhea, etc. Sometimes, these symptoms develop into airway diseases such as pharyngitis, bronchitis, etc., central nervous system diseases such as nonpyogenic meningitis, encephalitis, paralysis, etc., exanthematous diseases on the mucosae or skin, myositis, or conjunctivitis.
Astrovirus has a positive single-stranded RNA genome and is manifested by rotavirus-like enteritis symptoms, which have been regularly reported to the surveillance system run by the Korea Centers for Disease Control and Prevention. Once infected, astrovirus has an incubation period of 34 days, and is manifested by accompanying symptoms such as shivering, diarrhea, headaches, vomiting, stomachaches, pyrexia, etc. In Korea, enteritis in young children is annually prevalent in fall and winter. It was analyzed that 28% of childhood diarrhea is caused by astrovirus.
Adenovirus is known to have a positive stranded DNA genome and cause a variety of diseases such as acute respiratory diseases, gastroenteritis, epidemic conjunctivitis, meningitis, and hemorrhagic cystitis, depending on serotype.
Such enteric viruses survive in natural ecosystems while maintaining their infectivity for a long time, and when such enteric viruses are released from a human body, the enteric viruses repeat the infection cycle in a human body. The viruses are easily spread because people are infected with a small amount of the viruses, and spread thorough tiny droplets of water, clothing or bedding, person-to-person transmission, or infections caused by contamination of surrounding environments occur easily, and secondary and tertiary infections also often occur via families or people around infected persons. Most enteroviral infections are caused by physical contact among people. The enteric viruses are detected in the mouth, larynx and intestines, and released from the human body in the form of oral secretions or feces. In general, the contamination (of hands, dinnerware, food, etc.) with the feces often becomes a source of infection, and saliva discharged by coughing may become a direct/indirect source of contamination.
The probability of mass food poisoning caused by the same source of contamination has increased with the development of the food service industry, a rise in national income, an increase in imported foods, the establishment and enlargement of group feeding systems, etc. Further, the food poisoning viruses may directly or indirectly cause additional social and financial problems because they have a rapid transmission rate of infection and may progress into a secondary infection. Last year, approximately 7,269 food poisoning patients in a total of 104 cases were reported in Korea (based on statistical data from the Korea Food & Drug Administration). Also, annually, three to five billion diarrhea patients are reported worldwide, and, among these, approximately 10 million patients die. In particular, diarrhea is a real problem because diarrhea is not a disorder having severe symptoms like influenza or tuberculosis but it affects daily life and industrial activities, resulting in serious economic losses.
A method of rapidly diagnosing a causative virus (an etiologic agent) is required to prevent such additional infections and treat patients at an early stage. However, it is difficult to identify an etiologic agent since symptoms are similar in the case of acute enteritis. Currently used methods of diagnosing a virus causing acute enteritis include a cell culture method, a method based on an antigen-antibody reaction, a gene identification method, etc., but have a drawback in that they require expensive equipment, specialists, and costs, and have problems such as reduced sensitivity, outbreaks of mutants, a long-term trial period, etc.
Therefore, there is a need for development of a method of rapidly and accurately detecting viruses causing acute enteritis at low cost without any additional devices.